The disk was partionned that way :
30M Ununsed part (for windows reinstall)
+ 19Gb Single Ntfs part (with WIN XP Home)

You can decide to Wipe out the XP (you paid for it),
or shrik the partition to a few GB (50%) then create
at least one Linux Part and swap.

I'll suggest to choose ext3 as filesystem
because it can be read from other OS like windows.
I was wondering where swap part shall be placed on the disk for
best performances ? I choose at the end, I am not sure the rule :
2*sizeof(RAM) is allways valid, but it should at least one time (see swsusp)

The Windows XP filesystem is NTFS, and is read only on linux
(can be writeable tough) but can be converted to VFAT.
Windows 2000 provided a tool to do the ntfs2vfat conversion, but it
seems they removed it. Anyway you can still use commercial sofware :
PowerQuest/Partition Magic 8

Knoppix (Debian based and compatible as Testing/Unstable).
can be used as a Boot CD or Installed to the HD.
Knoppix is known to be like a demo disk to show how
Gnu/linux looks like, but Once booted you get a fully operational
system so fairly usable.
The Next step is to copy the system if you want to use it
from you harddrive.
This can be easly done

by repartitionning the disk with qtparted
( Windows partition can be resized also)

Debian is allways compared to Mandrake, poeple agrea to say that debian
is more modularized and closer to linux hacking so more complicate
while Mandrake is fast and easy to install and use.
I would add that knoppix is easier than Mandrake to install a bit tricker to
administrate but it worth to be tested (even if you are not sure to install it)

2.4 KERNEL

I use a patched kernel (w/ acpi and dri)
if you want to use it on debian (or knoppix etc)
see
http://rzr.online.fr/linux.htm
There is one thing i don't understand : keyboard is lock during booting process
only kdm wake it up ?

Short summary: It's a hardware problem (usually). Transient Line-noise/crosstalk persuades the PIC that something happened; this can result in a 'dummy' interrupt being raised, which happens to be IRQ7 with intel's 8259 design.The problem could possibly also be caused by (or instead be caused by) a device driver not properly masking its interrupts before servicing, this would be the suspect if the IRQ7's were happening in bursts, or more often than 'several' per day. (Source and additional information)
Since the message itself is harmless, it's enough to adjust the default loglevel outplut of klogd (the -c opion) in the syslogd bootscript. See man klogd for details. You can also try recompiling the kernel and unset CONFIG_LOCAL_APIC.
http://test.linuxfromscratch.org/faq/#spurious-8259A-interrupt
Q1. What is it?
A1. The 8259A/82C59A-2 is a programmable interrupt controller (PIC). It
is designed to allow prioritizing and handling of hardware interrupt
requests from peripheral devices, mainly in a PC environment.
http://groups.google.com/groups?q=spurious+interrupt+8259&hl=de&scoring=d&selm=3C174EDD.9090306%40hotmail.com&rnum=10